workflows: update unstable nightly builds for 3.0 (#9168)

Signed-off-by: Patrick Stephens <[email protected]>

.github/workflows/cron-unstable-build.yaml

@@ -13,8 +13,7 @@ on:
   # Run nightly build at this time, bit of trial and error but this seems good.
   schedule:
     - cron: "0 6 * * *" # master build
-    - cron: "0 12 * * *" # 2.2 build
-    - cron: "0 18 * * *" # 2.1 build
+    - cron: "0 12 * * *" # 3.0 build
 
 # We do not want a new unstable build to run whilst we are releasing the current unstable build.
 concurrency: unstable-build-release
@@ -52,16 +51,10 @@ jobs:
           echo "cron_branch=master" >> $GITHUB_ENV
         shell: bash
 
-      - name: 2.2 run
+      - name: 3.0 run
         if: github.event_name == 'schedule' && github.event.schedule=='0 12 * * *'
         run: |
-          echo "cron_branch=2.2" >> $GITHUB_ENV
-        shell: bash
-
-      - name: 2.1 run
-        if: github.event_name == 'schedule' && github.event.schedule=='0 18 * * *'
-        run: |
-          echo "cron_branch=2.1" >> $GITHUB_ENV
+          echo "cron_branch=3.0" >> $GITHUB_ENV
         shell: bash
 
       - name: Output the branch to use